The radio recombination lines of hydrogen

Peach, G.

doi:10.1016/j.asr.2013.08.020

Cited by 4 publications

(4 citation statements)

References 17 publications

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“…Of the first type is the magnetically confined fusion plasma, with its rich variety of atomic processes [40][41][42][43][44][45][83][84][85], notably in the boundary region [22][23][24][25][26][27][28], where perturbation of the atomic radiators by both electric and magnetic fields can be significant, and where new developments in Stark broadening theory [29][30][31][32][86][87][88] may lend themselves to useful applications of the Runge-Lenz-Pauli operator, as has indeed already been shown in [32,89]. Of the second type are the dilute space plasmas found in galactic H II regions, where analysis of the radio recombination spectral line broadening encounters particular problems associated with the very large principal quantum numbers [47][48][49][50][51][52][53][54][55]. The very useful recurrence relation method is now routinely applied, not only to such spectra, but in both Stark broadening theory in general [89,90] and to the spectral properties of non-equilibrium plasmas [91], as well as to kinetics and radiation transport [92].…”

Section: Discussionmentioning

confidence: 96%

“…Far higher principal quantum numbers than in laboratory plasmas are attainable in the radio recombination spectra observed from galactic H II regions [46], whose lines are broadened both by electron and ion collisions. The theory of collisional line broadening, invaluable for diagnostic purposes, has been developed in [47][48][49][50], while additional aspects of ion collisions (perturbation by an ion microfield background and ion-induced dipole interactions) are discussed in [36,51]. For the evaluation of the required radial matrix elements in [49], a factorization (ladder operator) method [9][10][11], originally pioneered in astrophysical applications by Burgess [52], was found to be extremely convenient in enabling the evaluation of hypergeometric functions of large argument to be avoided entirely, and the use of factorials of large numbers much reduced [53].…”

Section: Introductionmentioning

confidence: 99%

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On the Runge–Lenz–Pauli vector operator as an aid to the calculation of atomic processes in laboratory and astrophysical plasmas

Hey

2015

J. Phys. B: At. Mol. Opt. Phys.

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On the basis of the original definition and analysis of the vector operator by Pauli (1926 Z. Phys. 336–63), and further developments by Flamand (1966 J. Math. Phys. 7 1924–31), and by Becker and Bleuler (1976 Z. Naturforsch. 517–23), we consider the action of the operator on both spherical polar and parabolic basis state wave functions, both with and without direct use of Pauli’s identity (Valent 2003 Am. J. Phys. 71 171–75). Comparison of the results, with the aid of two earlier papers (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641–64, Hey 2007 J. Phys. B: At. Mol. Opt. Phys. 4077–96), yields a convenient ladder technique in the form of a recurrence relation for calculating the transformation coefficients between the two sets of basis states, without explicit use of generalized hypergeometric functions. This result is therefore very useful for application to Stark effect and impact broadening calculations applied to high-n radio recombination lines from tenuous space plasmas. We also demonstrate the versatility of the Runge–Lenz–Pauli vector operator as a means of obtaining recurrence relations between expectation values of successive powers of quantum mechanical operators, by using it to provide, as an example, a derivation of the Kramers–Pasternack relation. It is suggested that this operator, whose potential use in Stark- and Zeeman-effect calculations for magnetically confined fusion edge plasmas (Rosato, Marandet and Stamm 2014 J. Phys. B: At. Mol. Opt. Phys. 105702) and tenuous space plasmas ( H II regions) has not been fully explored and exploited, may yet be found to yield a number of valuable results for applications to plasma diagnostic techniques based upon rate calculations of atomic processes.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

On the Runge–Lenz–Pauli vector operator as an aid to the calculation of atomic processes in laboratory and astrophysical plasmas

Hey

2015

J. Phys. B: At. Mol. Opt. Phys.

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“…Observations of Rydberg transitions will provide exquisite tests of models of the upper photosphere, chromosphere, and corona. Detailed comparisons with models will also demand improved understanding of interesting physics, especially regarding collisional linebroadening, which remains controversial for low-density plasmas (e.g., Peach 2014;Hey 2014).…”

Section: Recombination Linesmentioning

confidence: 99%

Solar Science with the Atacama Large Millimeter/Submillimeter Array—A New View of Our Sun

et al. 2015

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The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful tool for observing the Sun at high spatial, temporal, and spectral resolution. These capabilities can address a broad range of fundamental scientific questions in solar physics. The radiation observed by ALMA originates mostly from the chromosphere -a complex and dynamic region between the photosphere and corona, which plays a crucial role in the transport of energy and matter and, ultimately, the heating of the outer layers of the solar atmosphere. Based on first solar test observations, strategies for regular solar campaigns are currently being developed. State-of-the-art numerical simulations of the solar atmosphere and modeling of instrumental effects can help constrain and optimize future observing modes for ALMA. Here we present a short technical description of ALMA and an overview of past efforts and future possibilities for solar observations at submillimeter and millimeter wavelengths. In addition, selected numerical simulations and observations at other wavelengths demonstrate ALMA's scientific potential for studying the Sun for a large range of science cases.

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“…New calculations of complete Stark broadened profiles for 15 radio recombination lines of hydrogen with the principal quantum number of the upper level n between 102 and 274, have been performed recently (Peach 2014). Electron and proton impact has been included and it has again been confirmed that for the radio recombination lines electronimpact broadening is the dominant broadening mechanism.…”

Section: Transitions In Hydrogenic and Helium-like Systemsmentioning

confidence: 99%

Division B Commission 14 Working Group: Collision Processes

Peach¹,

Dimitrijević²,

Barklem³

2015

Proc. IAU

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Since our last report (Peach & Dimitrijević 2012), a large number of new publications on the results of research in atomic and molecular collision processes and spectral line broadening have been published. Due to the limited space available, we have only included work of importance for astrophysics. Additional relevant papers, not included in this report, can be found in the databases at the web addresses provided in Section 6. Elastic and inelastic collisions between electrons, atoms, ions, and molecules are included, as well as charge transfer in collisions between heavy particles which can be very important.

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The radio recombination lines of hydrogen

Cited by 4 publications

References 17 publications

On the Runge–Lenz–Pauli vector operator as an aid to the calculation of atomic processes in laboratory and astrophysical plasmas

On the Runge–Lenz–Pauli vector operator as an aid to the calculation of atomic processes in laboratory and astrophysical plasmas

Solar Science with the Atacama Large Millimeter/Submillimeter Array—A New View of Our Sun

Division B Commission 14 Working Group: Collision Processes

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